Is There Ever An End To The Black Algae Saga????

by Cindy
(Mesa, Az)

I have read all of your advice and tried it all out. I have never had a chemical for black algae do the trick. I got suckered into another 40 buck bottle from Leslie's. He said, "They can't keep it on the shelf because the customers swear by it." Baloney!

I believe I have more algae since using it. PLUS, my pool turned green after the application. I have followed all of your advice to a T. Where does it end? Please advise. My pool is 15,000 gallons and has a DE Earth filter. The water is very hard.

They told me it could just be the water company. I had the water tested before doing any chemical applications. After draining my pool last year, the hardness was back up to where it was prior to draining within 8-12 weeks. I asked how I'm ever going to lick an algae problem when the hardness is so high.

The pool guy told me my hardness was acceptable to treat for algae. On my strips it is off the charts. Any further suggestions. I'd appreciate any help you can offer.

Thanks for the question Cindy

I know first hand about black algae problems and about how hard the water is in Mesa. That's where the majority of my pools were. Some in Phoenix and Tempe, but mostly in Mesa. Your first tip should have been when the pool guy at Leslie's said "customers swear by it".

I would have asked him what HE uses to get rid of black algae. How HE did it. Has HE ever used this product? If not, why not?

Black Algae

First, I would encourage you to get a Taylor FAS-DPD K-2006 test kit. It's the best on the market and will give you the most accurate reading. It's the one I've used since 1999 and the one most pool professionals use.

Water Testing Kit

Pool Water Testing

The question says test strips are used and the hardness is off the charts. With the DPD kit you'll know exactly what the hardness is. Your pool probably turned green, not from algae, per se, but sometimes when an algaecide is used it messes with the pH.

If it was an emerald green and not a normal solid green associated with green algae, it's more than likely a pH issue. That's easy to adjust.

Swimming Pool pH Levels

The only way to reduce water hardness is to drain 1/3 - 1/2 of the water with fresh water.
But like the question said, it will be raised in the coming
weeks from adding new hard tap water due to evaporation, drag-off, etc... You can look into a local pool water delivery service. Ask them what the hardness of the their water is. If it's lower than you fill water, you might want to go with them.

Pool Water Delivery

You need a good black algae algaecide that is called "PolyQuat 60%". This doesn't "kill" the algae, but will prepare it for the shock treatment. If the algaecide has copper in it, don't buy it. Check your last bottle of algaecide for copper. ProTeam has a good one. Black Treat Algaecide from United Chemicals is also good.

Pool Supplies

First is to get a wire brush (only with concrete pool, not vinyl) and brush the affected areas. This loosens up the black algae spots. Drop your pH to 7.0ppm.

Swimming Pool pH Levels

Add the initial dose of PolyQuat 60% black algae algaecide. Allow to circulate for a couple of hours.

During this time, try the best you can to scrub the spots with a chlorine tab. If you can't, use a measured dose of granular chlorine just to the spots. Don't use granular to shock. It has a high dose of calcium and you don't need more hardness in your pool.

Shock the pool. For your 15,000 gallons pool you'll use 2 gallons of liquid chlorine.

Pool Shock

Keep brushing with the wire brush and grinding in the Tri-chlor chlorine tablets. Black algae has layers. This is why it's one of the worst kinds of algae. It takes multiple steps to get rid of it. Test your chlorine daily and keep it above 7ppm as best you can. Remember to use liquid chlorine.

Sodium Hypochlorite

Add another dose of PolyQuat 60% and keep the chlorine level up. Test the chlorine every day, maybe twice per day, if you can. Try to keep the pool pH around 7.0ppm the best you can. Chlorine is more active at lower pH levels. Keep the pool water circulating 24/7.

If the black algae is reoccurring, you might want to use a black algae algaecide on a weekly basis. My experience has shown that black algae seems to be removed by high chlorine, scraping the layers off with a wire brush, and rubbing Tri-Chlor tablets on the exposed algae.

I think many people believe that simply putting in an algaecide will do the trick. This is one part, but far from the whole truth. Removing black algae takes alot of effort. Hope this helps and good luck with your pool. Have a great swimming season.


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